The present invention relates to methods for vehicle navigation and guidance, and more particularly, to methods and systems for determining a position of a reference vehicle relative to an autonomous vehicle.
An autonomous vehicle has an independent navigation or guidance system that is not directly controlled by another vehicle. Precise positioning of autonomous vehicles, such as aircraft, watercraft and automobiles, relative to one or more stationary or moving references is commonly required for space, air, and surface operations such as ground or carrier-based landing, in-flight aircraft refueling, aircraft formation maneuvers, spacecraft docking, and collision avoidance. Conventional techniques for determining a position of a vehicle relative to a stationary or moving reference includes digital imagery processing, active sensor techniques (e.g., radar or laser techniques), and global positioning techniques (GPS). Digital imagery processing and active sensor techniques typically require sophisticated, expensive sensor equipment and human pilot interaction with the autonomous vehicle, which may be problematic in certain operations such as aircraft refueling or formation maneuvers. Conventional GPS techniques require four GPS satellite transmitters, which are susceptible to incidental or overt disruptions in transmissions to an autonomous vehicle, causing delays and errors in determining the position of the autonomous vehicle relative to the GPS satellites.
Therefore, a need exists for systems and methods that overcome the problems noted above and others previously experienced for determining the position of an autonomous vehicle.